Wheels of Fate

The Wheels of Fate is a special feature that has some similarities with slot machines. You perform this in the same place that you open Booster Packs (Click the "Store"-button at the top, and then "Open Pack" at the bottom right). To spin the wheels you first drag a Treasure Chest to the altar. The cost in gold to spin the chest will be displayed on the "Roll"-button at the bottom of the screen. The amount of gold depends on the rarity of the chest.

Cost to spin a chest:
 * Common 1,200 Gold
 * Uncommon 3,100 Gold
 * Rare 8,500 Gold
 * Legendary 30,000 Gold
 * Primal 0 Gold

Rewards
It does not matter which rarity of Treasure Chest you spin, the chances of winning specific prizes are the same. The reason for the difference in cost is due to the chance of winning an upgrade of the Treasure Chest rarity. Each Treasure Chest can only be spun once, unless you win extra spins. Most of the rewards offer you to "Pay to Spin Again" (PS), this allows you to spin the same chest one more time. Rewards such as cards or equipment come in different rarities; common, uncommon and rare.

The Mercenaries, PvE cards, PvE card equipement, Alternate Art Cards and Sleeves are exclusive to the Wheels of Fate. The rewards (colored blue in the screenshot) from the top are


 * PS
 * Free Spin
 * Upgrade Chest
 * Mercenary + PS (common: "Ashahsa, Windbourne Acolyte", uncommon: "Xorak, the Flamehand", rare: "Puck, Dream Bringer")
 * PvE Card Equipment + PS (see below)
 * Upgrade Chest + PS
 * PvE Card + PS (common: Lightning Elemental, uncommon: Water Elemental, rare: Air Elemental)
 * Sleeves + PS (common: Windbourne Acolyte, uncommon: Veteran Gladiator, rare: Wrathwood Colossus)
 * Alternate Art Card + PS (common: Windbourne Acolyte, uncommon: Veteran Gladiator, rare: Wrathwood Colossus)
 * Upgrade Chest Twice + PS
 * PvP Rare Card + PS (Can also be a legendary card)

If you get any gold icons you win gold in addition to any other reward. 1 icon gives you 500, 2 gives you 2500, and 3 gold icons gives you 5000 gold. If you get three matching icons which are also red, you get an "exclusive" reward, which at the moment is a Booster Pack.

The chances of winning is not specified, but there is a thread on the official forums where data is being gathered.

PvE Card Equipment
The PvE card equipment is matched with the three PvE cards you can win, with each card being able to hold two pieces of equipment.
 * Rare: Sky Walker and Bubble Mail
 * Uncommon: North Wind Chimes and Electric Flail
 * Common: Aqua Mask and Spark Mitts